Heat oven to 400 degrees. Peel and cut sweet potatoes into a large dice. Toss in a large bowl with 1 tablespoon olive oil, 1/2 teaspoon cumin, 1/2 teaspoon paprika, 1/2 teaspoon salt. Pour out onto a baking sheet and bake for 25-30 minutes until tender. Cut the summer squash into the same large dice and toss in the same bowl with 1 tablespoon olive oil, 1/2 teaspoon cumin and 1/2 teaspoon paprika and 1/2 teaspoon salt. When the sweet potatoes are done, switch the oven to broil, remove the potatoes to a plate to cool, and using the same pan, pour out the squash into a single layer and cook under the broiler for 5-7 minutes until slightly browned. While the squash is under the broiler, shuck the corn and cut the kernels from the cobb. In a large bowl combine the raw corn kernels, the cooked squash and sweet potatoes, along with the chopped cilantro, red onion, lime juice and 1 additional tablespoon olive oil. Stir well and season with fresh ground black pepper and additional salt if needed.